There used to be a feature for that in MediaWiki IIRC, but it had ginormous privacy concerns. Because unlike, say, Facebook or Discord, users could not switch it off. It also didn't have idle or sleep mode, so if someone were to leave their pc on overnight, it'd mark them as "online" all night. It was crude, uncustomizable and unmaintainable. I've only ever seen it at a non-Fandom wiki, where it stopped working after a MediaWiki upgrade so I assume it was just dropped from the software.

And let's be frank: it's nobody's business who is online when.

I did some double checking. It still exists; it's the WhosOnline extension, which I don't think Staff will enable for you upon request but you can always try. The issues about the absence of idle/afk/opt-out functions have not been fixed.

Okay, thanks!

Quick question, where should I add the extension?

Also, do you mind giving the CSS for the thumbs up button for comments?

You cannot add extensions yourself. Click the WhosOnline link for more info on it. If you are asking questions like that about extensions, you probably shouldn't mess with it.

The "thumbs up" is not something you can add. It is an integrated part of the Forum feature; which newer wikis don't have and older wikis will have removed starting mid-January.

It isn't precise, but you could use Status. It isn't precise because all it does is just check the timestamp of the user's last logged activity and then makes a guess based on that. However, it is better than nothing if you really want something like it.

Thank you!